To achieve a high separation efficiency of a packing column which is used in a thermal separation process, it is required to uniformly distribute the liquid phase over the column cross-section. When the liquid trickles through the packing, independent of whether the same consists of a random packed bed or whether it is a stacked or structured packing, an unequal distribution of the liquid occurs, which increases with the packing height trickled through. It therefore is required to limit the height of a packing and collect the liquid after passing through a packing and newly distribute the liquid over the next following packing.
The liquid dripping out of a packing can be collected by a column tray designed as liquid collector and can be passed from there into a column tray designed as liquid redistributor, cf. M. Baerns et al., Technische Chemie, 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, p. 334, Fig. 9.51.